Many varieties of track lighting or rail electrode systems exist. These generally include various designs of spatially separated electrodes that are located parallel to the linear axis of the track. For lighting applications, common “track” or “monorail” systems generally have at least two continuous parallel electrodes within a mechanical housing, forming a substantially rectangular, prismatic or concentric cross-section with continuous electrode contact surfaces along the length of the track. For the purposes of this disclosure, these electrode systems are considered to have uniform spacing with respect to the axis at different locations along the axis, or “uniform axial spacing”. Flexible parallel cable pairs held under tension in free space or embedded in a ribbon cable are other types of laterally-displaced rail electrodes with uniform axial spacing.
Although the radial separation distances between the track axis and the surface of concentric electrodes are different from one another, the distances from the track axis to each electrode is substantially uniform at different locations along the axis. This is also considered to have uniform axial spacing.
Co-owned U.S. Pat. No. 9,303,854 entitled “Electrical Rail Systems with Axially Interleaved Contact Arrays” issued on Apr. 5, 2016 and is incorporated by reference in its entirety herein. Pairs of electrodes in some embodiments of the referenced patent have fixture contact surfaces that wrap around a central electrode system axis such that the spacing of the electrode contact surfaces are at a uniform spacing from the central axis of the pair regardless of whether the electrodes are of a circumferential contact band form or the helical form. Fixtures attached to these axially-interleaved contact array systems may be rotated around the axis of the electrode system, but the distance to each of the fixture contacts from the axis does not change with this rotation. The coaxial and axially interleaved track systems provide additional pointing capability compared to linear rail systems as a result of adding this rotation to the linear translation of parallel electrode systems.
While track lighting systems may provide more flexibility than stationary lighting fixtures, they do not meet all the needs for easily reconfiguring the lighting distribution in a space. Some prior art rail systems are designed to be customized through bending during installation but are typically difficult to bend in all directions because of their generally rectangular cross section or other asymmetric cross-sectional structure. Also, to aim the light output of a lighting fixture attached to prior art electrode systems, additional mechanical knuckle joints, gimbals, movable optical elements or other means are often required to direct light along different directions. These elements may increase the weight, size, cost and complexity of the fixtures and may still limit the ease of pointing fixtures where desired. In addition, if parallel electrodes are not mounted continuously to a supporting substrate, some form of mechanical tensioning system or mechanical spacer is generally needed to hold the electrodes in the proper position relative to each other and the rail axis. This spacing maintenance may result from a continuous spacer preventing relative movement of electrodes or a series of discrete spacer elements that periodically attach between electrodes. Periodic spacers holding electrodes in space are generally restricted to simple systems for supplying a voltage to two fixture contacts to simply supplying power to an attached fixture. The present disclosure includes systems and methods that address one or more of these issues in the prior art.